package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    //异步处理线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();
    //秒杀lua脚本
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    //初始化脚本
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    //redisson
    @Resource
    private RedissonClient redissonClient;
    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    // 创建阻塞队列
//    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);

    // 代理对象
    private IVoucherOrderService proxy;

    //在类初始化之后执行，因为当这个类初始化好了之后，随时都是有可能要执行的
    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    // 异步处理订单
    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户id
        Long userId = UserHolder.getUser().getId();
        //获得新的订单id
        Long orderId = redisIdWorker.nextId("order");
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(), String.valueOf(orderId)
        );
        //判断结果
        int res = result.intValue();
        if (res != 0) {
            //2.判断结果是否为0
            //0-成功  1-失败  2-排队中
            return Result.fail(res == 1 ? "库存不足" : "不能重复下单");
        }
//        VoucherOrder voucherOrder = new VoucherOrder();
//        // 2.3.订单id
//        voucherOrder.setId(orderId);
//        // 2.4.用户id
//        voucherOrder.setUserId(userId);
//        // 2.5.代金券id
//        voucherOrder.setVoucherId(voucherId);
        //3.获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
//        // 2.6.放入阻塞队列
//        orderTasks.add(voucherOrder);

        //3.返回订单id
        return Result.ok(orderId);
    }
//    public Result seckillVoucher(Long voucherId) {
//        //获取用户id
//        Long userId = UserHolder.getUser().getId();
//        //获得新的订单id
//        Long orderId = redisIdWorker.nextId("order");
//        //1.执行lua脚本
//        Long result = stringRedisTemplate.execute(
//                SECKILL_SCRIPT,
//                Collections.emptyList(),
//                voucherId.toString(), userId.toString(), String.valueOf(orderId)
//        );
//        //判断结果
//        int res = result.intValue();
//        if (res != 0) {
//            //2.判断结果是否为0
//            //0-成功  1-失败  2-排队中
//            return Result.fail(res == 1 ? "库存不足" : "不能重复下单");
//        }
//        VoucherOrder voucherOrder = new VoucherOrder();
//        // 2.3.订单id
//        voucherOrder.setId(orderId);
//        // 2.4.用户id
//        voucherOrder.setUserId(userId);
//        // 2.5.代金券id
//        voucherOrder.setVoucherId(voucherId);
//        //3.获取代理对象
//        proxy = (IVoucherOrderService) AopContext.currentProxy();
//        // 2.6.放入阻塞队列
//        orderTasks.add(voucherOrder);
//
//        //3.返回订单id
//        return Result.ok(orderId);
//    }

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //5.一人一单
        Long userId = voucherOrder.getUserId();
        //5.1查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        //5.2判断是否已经购买过
        if (count > 0) {
            //已经购买过
//            return Result.fail("已经购买过");
            log.error("用户{}重复下单", userId);
            return;
        }
        //6.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock", 0)//减库存不能小于0
                .update();
        if (!success) {
            //扣减失败
            log.error("库存不足");
            return;
        }
        //7.创建订单
//        VoucherOrder order = new VoucherOrder();
//        //7.1订单id
//        long orderId = redisIdWorker.nextId("order");
//        order.setId(orderId);
//        //7.2用户id
//        order.setUserId(userId);
//        //7.3代金卷id
//        order.setVoucherId();
        save(voucherOrder);
    }
//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        // 1.查询优惠卷
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        //2.判断秒杀是否开始
//        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
//            //未开始
//            return Result.fail("秒杀尚未开始");
//        }
//        //3.判断秒杀是否结束
//        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
//            //已结束
//            return Result.fail("秒杀已结束");
//        }
//        //4.判断库存是否充足
//        if (voucher.getStock() < 1) {
//            //库存不足
//            return Result.fail("库存不足");
//        }
//
//        //8.返回订单id
//        Long userId = UserHolder.getUser().getId();
////        //创建锁对象
////        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//        //获取锁对象
//        boolean isLock = lock.tryLock();
//        //判断是否获取锁成功
//        if (!isLock) {
//            //获取锁失败，返回失败消息
//            return Result.fail("不允许重复下单");
//        }
//        try {
//            //获取代理对象
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);
//        }finally {
//            //释放锁
//            lock.unlock();
//        }
//    }
    private class VoucherOrderHandler implements Runnable {

        @Override
        public void run() {
            while (true) {
                try {
                    // 1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create("stream.orders", ReadOffset.lastConsumed())
                    );
                    // 2.判断订单信息是否为空
                    if (list == null || list.isEmpty()) {
                        // 如果为null，说明没有消息，继续下一次循环
                        continue;
                    }
                    // 解析数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    // 3.创建订单
                    createVoucherOrder(voucherOrder);
                    // 4.确认消息 XACK
                    stringRedisTemplate.opsForStream().acknowledge("s1", "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    //处理异常消息
                    handlePendingList();
                }
            }
        }
    }
    private void handlePendingList() {
        while (true) {
            try {
                // 1.获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 0
                List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                        Consumer.from("g1", "c1"),
                        StreamReadOptions.empty().count(1),
                        StreamOffset.create("stream.orders", ReadOffset.from("0"))
                );
                // 2.判断订单信息是否为空
                if (list == null || list.isEmpty()) {
                    // 如果为null，说明没有异常消息，结束循环
                    break;
                }
                // 解析数据
                MapRecord<String, Object, Object> record = list.get(0);
                Map<Object, Object> value = record.getValue();
                VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                // 3.创建订单
                createVoucherOrder(voucherOrder);
                // 4.确认消息 XACK
                stringRedisTemplate.opsForStream().acknowledge("s1", "g1", record.getId());
            } catch (Exception e) {
                log.error("处理pendding订单异常", e);
                try {
                    Thread.sleep(20);
                } catch (Exception ex) {
                    ex.printStackTrace();
                }
            }
        }
    }
    // 用于线程池处理的任务
    // 当初始化完毕后，就会去从对列中去拿信息
//    private class VoucherOrderHandler implements Runnable {
//
//        @Override
//        public void run() {
//            while (true) {
//                try {
//                    // 1.获取队列中的订单信息,阻塞方法
//                    VoucherOrder voucherOrder = orderTasks.take();
//                    // 2.创建订单
//                    handleVoucherOrder(voucherOrder);
//                } catch (Exception e) {
//                    log.error("处理订单异常", e);
//                }
//            }
//        }
//    }
        private void handleVoucherOrder(VoucherOrder voucherOrder) {
            //1.获取用户
            Long userId = voucherOrder.getUserId();
            // 2.创建锁对象
            RLock redisLock = redissonClient.getLock("lock:order:" + userId);
            // 3.尝试获取锁
            boolean isLock = redisLock.tryLock();
            // 4.判断是否获得锁成功
            if (!isLock) {
                // 获取锁失败，直接返回失败或者重试
                log.error("不允许重复下单！");
                return;
            }
            try {
                //注意：由于是spring的事务是放在threadLocal中，此时的是多线程，事务会失效
                proxy.createVoucherOrder(voucherOrder);
            } finally {
                // 释放锁
                redisLock.unlock();
            }
        }
}
